Kinetics of the Reactions of Hydroxyl Radicals with Furan and Its Alkylated Derivatives 2-Methyl Furan and 2,5-Dimethyl Furan

Abstract

Furans are promising second generation biofuels with comparable energy densities to conventional fossil fuels. Combustion of furans is initiated and controlled to a large part by reactions with OH radicals, the kinetics of which are critical to understand the processes occurring under conditions relevant to low-temperature combustion. The reactions of OH radicals with furan (OH + F, R1), 2methyl furan (OH + 2-MF, R2), and 2,5-dimethyl furan (OH + 2,5-DMF, R3) have been studied in this work over the temperature range 294 to 668 K at pressures between 5 mbar and 10 bar using laser flash photolysis coupled with laser-induced fluorescence (LIF) spectroscopy to generate and monitor OH radicals under pseudo-first-order conditions. Measurements at p ≤ 200 mbar were made in N2, using H2O2 or (CH3)3COOH radical precursors, while those at p ≥ 2 bar were made in He, using HNO3 as the radical precursor. The kinetics of the reactions R1-R3 were observed to display a negative dependence on temperature over the range investigated, indicating the dominance of addition reactions under such conditions, with no significant dependence on pressure observed. Master equation calculations are in good agreement with the observed kinetics, and a combined parameterisation of addition channels and abstraction channels for R1-R3 is provided on the basis of this work and previous shock tube measurements at higher temperatures. This work significantly extends the temperature range previously investigated for R1 and represents the first temperature-2 dependent measurements of R2 and R3 at temperatures relevant for atmospheric chemistry and lowtemperature combustion.

Analysis of Furan in Red Pepper Powder Treated by Three Methods-Boiling, Roasting, and Frying

“…In untreated dried red pepper powder the furan level was 4.58 ng/g. In the previous study, furan production was found to be temperature-dependent in hot coffee samples ( 28 ). The furan levels in the roasted red pepper samples also increased with increasing temperature and time conditions.…”

NO<sub>3</sub> chemistry of wildfire emissions: a kinetic study of the gas-phase reactions of furans with the NO<sub>3</sub> radical

“…A number of reference compounds were used for each VOC, chosen so that the reference rate was roughly within a factor of five of the expected unknown rate, and with an attempt to use different references that had both faster and slower NO 3 reaction rates than the VOC. Reaction rates of the reference compounds (Table 2) with NO 3 addition to the C2 carbon followed by O 2 addition to the C5 carbon (Berndt et al, 1996), analogous to the OH addition reaction (Bierbach et al, 1995;Mousavipour et al, 2009;Yuan et al, 2017;Whelan et al, 2020). However, some of the reference compounds used in the experiments will form such radicals.…”

“…Furan type compounds are removed from the atmosphere by reaction with the major oxidants OH, NO 3 and O 3 . There have been a number of studies on the rates of reaction of furan type compounds with the dominant daytime oxidant, OH (Lee and Tang, 1982;Atkinson et al, 1983;Wine and Thompson, 1984;Bierbach et al, 1992Bierbach et al, , 1994Bierbach et al, , 1995Aschmann et al, 2011;Ausmeel et al, 2017;Whelan et al, 2020). However, there have been fewer studies on the rates of reaction of furan type compounds with the major night-time oxidant, NO 3 (Atkinson et al, 1985;Kind et al, 1996;Cabañas et al, 2004;Colmenar et al, 2012).…”

NO<sub>3</sub> chemistry of wildfire emissions: a kinetic study of the gas-phase reactions of furans with the NO<sub>3</sub> radical

“…HO 2 could be generated in these experiments from the abstraction of an H atom by O 2 from a β-ONO 2 -RO radical with available H atoms. The initial NO 3 reaction with furans is not thought to form β-ONO 2 -RO 2 radicals, with NO 3 addition to the C 2 carbon followed by O 2 addition to the C 5 carbon (Berndt et al, 1997), analogous to the OH-addition reaction (Bierbach et al, 1995;Mousavipour et al, 2009;Yuan et al, 2017;Whelan et al, 2020). However, some of the reference compounds used in the experiments will form such radicals.…”

“…Furan-type compounds are removed from the atmosphere by reaction with the major oxidants OH, NO 3 , and O 3 . There have been a number of studies on the rates of reaction of furan-type compounds with the dominant daytime oxidant, OH (Lee and Tang, 1982;Atkinson et al, 1983;Wine and Thompson, 1984;Bierbach et al, 1992Bierbach et al, , 1994Bierbach et al, , 1995Aschmann et al, 2011;Ausmeel et al, 2017;Whelan et al, 2020). However, there have been fewer studies on the rates of reaction of furan-type compounds with the major nighttime oxidant, NO 3 (Atkinson et al, 1985;Kind et al, 1996;Cabañas et al, 2004;Colmenar et al, 2012).…”